Crowds spilled onto the road, chanting "do a skid, do a skid" at cars along Cooyong Street as authorities tried to wrap up the final night of the Braddon Fringe Festival.
Drinks were then thrown at a police car when it approached the group of motoring enthusiasts.
ACT police told The Canberra Times they responded to a handful of hoon driving incidents after the event finished.
They issued several defect notices and seized three vehicles as a result of hoon driving.
The rowdy behaviour capped off the third - and earlier largely orderly - day of the festival that turned parts of Braddon into an outdoor modified vehicle showroom.
Roaring engines, burning rubber and '80s hits also filled the streets on Saturday.
On Lonsdale Street, Ben Crombie's 1965 Rolls Royce silver shadow was on display.
Mr Crombie travelled to Canberra from Orange in New South Wales, with his wife Rebecca and son Enzo. He had been coming to Summernats since he was a teenager but this year was his first time showing a car at the Braddon Fringe Festival.
Over the years, Mr Crombie made a number of modifications to Rolls Royce, including fitting the car with a small block chev, but has left the body "fairly stock".
"It's a sort of timeless design. You just don't see Rolls Royces," he said.
"Gauges are aftermarket but I've got them made in a special style to suit the old style so I tried to make it to look original body wise, just lower to the ground and way more horsepower."
Mr Crombie said working on the car was a family affair, with both his wife and son helping with the modifications.
"An awesome part of the sport is to have a car that you can use with your family," he said.
While Summernats has often been touted as a major drawcard for interstate visitors to the capital, the festival in Braddon was also teeming with locals on Saturday.
Any other year, Ally Sweeney and her hot pink tow truck would be in the midst of the Summernats action, moving some of the most impressive modified street machines in town around the capital.
Last January, the pink truck was also parked on the rainbow roundabout but this year it was at the repairer after a crash took it out of action in October.
Four years ago, Ms Sweeney launched her own company TNA Towing and last year was entrusted to help deliver the top 50 Summernats cars competing for the number one prize.
"They put in hundreds of thousands of dollars of work into their cars and they entrust me with their pride and joy, to deliver them into the showroom," she said.
"It's a big honour."
She planned to be back at the festival next year - truck in tow.
For friends Tony and Ben, who asked to be referred to only by their first names, the event was as much about friendships as it was about cars.
The pair met at Summernats around 16 years ago. Not only have the pair become friends, but so have their families.
Speaking on the fringe festival, Tony said its establishment in Braddon has meant fewer cars were able to cruise through Lonsdale Street, which has taken away from the scene.
At the same time, he said the festival provided a family-friendly environment where Summernats goers could escape to if the crowds at the main venue in Exhibition Park became rowdy.
It comes as ACT police say they arrested two people at Exhibition Park for anti-social behaviour on Saturday.
